[edk2-buildtools] Problem Building - can't find PeCoffExtraActionLib

[David F. <df...@gm...>]

c:\edk2\Test\Test.dsc(...): error 4000: Instance of library class
[PeCoffExtraActionLib] is not found
        in [c:\edk2\MdePkg\Library\BasePeCoffLib\BasePeCoffLib.inf] [X64]
        consumed by module [c:\edk2\Test\testapp\testapp.inf]

I tried adding it to Test.dsc, using:

  BasePeCoffExtraActionLib|MdePkg/Library/BasePeCoffExtraActionLibNull/BasePeCoffExtraActionLibNull.inf


But still not working.


???

What am I missing?

TIA!!